I have an Intel Q9550. These are known to be great for overclocking. Last night I decided to give it a little try.
1.2v on CPU
1.4v on FSB
OC from 2.83Ghz to 3.570. This is on air!!!
I also have been tinkering with my 9800GTs in SLI. The stock is 670/975. I've been fiddling with it some, but it seems that on stock cooling it is really easy to overclock 740/1030 no problem and almost no temp increase. Strange.